A magnetic substance material which exhibits high magneto-optical properties while transmitting light will actualize optical isolators utilizing magneto-optical effect and high density magnetic recording, which are required for transfer of large amounts of information. This allows the production of electromagnetic materials necessary for transfer of large amounts of information. Therefore, development of materials having high magneto-optical properties has been desired.
Examples of known materials having high magneto-optical properties include magnetic garnet materials (for example, YIG and GdBiG) for long wavelengths (from 1.3 to 1.5 μm), and dilute magnetic semiconductor materials (for example, HgCdMnTe and CdMnTe) for short wavelengths (from 0.6 to 1 μm) (Non-patent Document 1). The magnetic garnet materials are practically used as optical isolators for optical information communication.
Non-patent Document 1: Katsuaki Sato, “Hikari to Jiki Kaiteiban” (Asakura Publishing Co., Ltd., 2001), Chapter 7, p. 177-191.